No. Enjoying good health and well-being is not a sign of weak faith, just as being tested is not the only sign of Allah's love for His servant. A believer is in a state of goodness under all circumstances: if Allah grants him blessings, he is grateful; and if hardship befalls him, he remains patient. The true measure is obedience to Allah and steadfastness upon His religion, not the frequency or absence of illness.
Many authentic texts explain the virtue of being patient during trials and that hardships expiate sins and elevate one's rank.
The Prophet ﷺ said:
"When Allah intends good for someone, He afflicts him with trials."
This means that the hardships a believer experiences may become a means of erasing sins and increasing reward if he remains patient and seeks Allah's reward.
However, this does not mean that a believer should wish for calamities, nor does it mean that someone who experiences fewer hardships has weaker faith than others.
Good health and well-being are among Allah's greatest blessings upon His servants. The Prophet ﷺ frequently supplicated to Allah for pardon and well-being.
Therefore, being protected from illness and calamities is a blessing that deserves gratitude; it is not evidence of deficient faith.
Rather, a Muslim is encouraged to constantly ask Allah for:
The Prophet ﷺ said:
"How wonderful is the affair of the believer! Indeed, all of his affairs are good..."
A believer has two situations:
He thanks Allah for the blessings He has granted him, such as health, safety, and stability.
He remains patient and hopes for Allah's reward.
In both situations, he is upon goodness.
Allah may test His servant through many things other than sickness, such as:
Therefore, it is not correct to measure the strength of faith solely by the amount of illness a person experiences.
The greatest criterion is steadfastness in obeying Allah and following His Messenger ﷺ.
Allah says:
"Say, 'If you truly love Allah, then follow me; Allah will love you.'"
(Qur'an 3:31)
If a servant consistently performs the obligatory acts of worship, avoids what Allah has forbidden, and remains grateful for Allah's blessings, these are among the greatest signs of goodness.
And Allah knows best.